Beat egg whites with an electric mixer. Gradually add powdered sugar, then powdered sugar. Poach the meringue on a baking tray lined with baking paper. I poached two sizes of ide meringue, the same size as the silikomart 8 and 15 cavities molds. Place in a 90°C fan-assisted oven for two hours, then turn off the oven and leave the meringue to dry for a further 1 hour.
Poach a little chestnut cream onto the larger meringue cookies. Set aside until ready to assemble.
In a bowl, mix the egg yolk with the sugar until slightly white. In a saucepan, bring 100ml of cream to the boil, remove from heat and pour the hot cream over the previous mixture. Return to the pan and cook over low heat until 82ºC. Remove from the heat and add the gelatine. Pour the hot cream over the chestnut cream and stir. Pour into 15-cavity silikomart mold halfway up and place in freezer. Allow to set for 15 minutes in the freezer, then add the smaller meringue on top. Return to freezer until ready to assemble.
Place the gelatine leaves in a large bowl of cold water. In a saucepan, heat the 50g crème liquide and the crème de marron. Mix well. Remove from heat and add the wrung-out, softened gelatine. Set aside. Whip the 200g chilled cream with an electric mixer. Add the chilled cream to the previous mixture and mix gently.
Assembly
Fill the silikomart cube x8 mold with chestnut mousse, then add the chestnut cream insert with the smaller meringue. Add a little more chestnut mousse and finish with the larger meringue. Freeze overnight.
Soften the gelatine in a container filled with cold water. Melt the white chocolate in the microwave. In a saucepan, heat water, sugar, glucose. Remove from heat and add the gelatine. Mix well. Pour over melted white chocolate and chestnut cream. Add liquid cream. Mix to blend well. Strain on contact and chill.
The next day, bring the glaze to around 35°C and pour over the still-frozen cubes.
I made dark chocolate chestnuts using the XiaoShenlu mold found on Amazon, and chocolate squares (with tempered dark chocolate) using a chocolate decorating sheet found on Meilleurduchef.com.